ES2228037T3 - VERTEBRAL BODY SEPARATOR DEVICE. - Google Patents

Abstract

A method and instrumentation particularly adapted for disc space preparation from an anterior approach to the spine. In one aspect, an expandable template is provided having guides to guide a cutting device for bilateral formation of openings in the disc space. In another aspect, an improved guide member is provided for guiding a cutting tool. Still further, the invention provides an improved double barrel guide sleeve with a central distraction extension and lateral non-distracting extensions. Optionally, the guide sleeve includes windows and covers to selectively cover the windows. An improved reamer with an internal chamber and optional modular coupling is also provided. A depth stop is provided to selectively engage a tool shaft and a guide sleeve to control tool penetration into the disc space. A method of using the disclosed instruments is also provided. <IMAGE>

Description

Vertebral body separator device.

The present invention generally concerns surgical procedures for spinal stabilization and, more specifically, to an instrumentation adapted to insert a spinal implant within the intervertebral disc space between adjacent vertebrae. More particularly, although some aspects of the invention may have other applications, the present invention It is especially suitable for the preparation of the disc space and implant insertion into a disc space from an access in General anterior to the spine.

Several surgical methods have been devised to the implant or fusion of devices in the disc space. For the merger between bodies have been used both previous accesses and later. In 1956, Ralph Cloward developed a method and a instrumentation for a fusion between spinal bodies of the cervical spine Cloward surgically extracted the material from the disk and placed a tubular drill guide with a large plate base and some tips on an alignment bar and then embedded the tips in adjacent vertebrae. Drilling guide served to maintain the alignment of the vertebrae and facilitated the reaming of the bone material adjacent to the disc space. The process reaming created a hole to accommodate a spike implant that is. Then the drill guide was removed after the rest of the process for the passage of the bone spike, which had a outside diameter significantly larger than the reaming hole and that the inside diameter of the drill guide. The removal of the drill guide left the implant phase of the spike completely unprotected

More recent techniques have advanced this concept and have provided more protection for sensitive tissue during the preparation of the disc space and the insertion of the spike. Such techniques have been applied to prior access to the lumbar spine In an approach, a template was provided unilateral to evaluate the space within the disc space. For a bilateral implant placement, had to rotate all the template device and visually align it to approximately 180º from the previous position. Thus, there was the possibility of operator error turning the device to the correct position. In addition, there was little guidance to ensure proper alignment of instruments shears that extend across the template.

An attempt to provide such alignment is the use of a guide wire that extends through a cannula-shaped cutting instrument, such as a trephine. Without However, for instruments with hollow cutting heads, typically there is no coupling between the inner walls of the head of Cut and guide wire. Thus, the guide wire can be bent between the portion that extends into the tissue and the guide wire entry into the cannula of the instrument. As a result, the hollow cutting head cannot remain in substantial alignment with the guide wire, resulting in the formation of an inappropriate opening. By consequently, there is still a need to have a Improved guide mechanism for cutting instruments.

Once one or more openings have been made initials in the disc space, the height of the disc space is normally separated to approximate normal height. Typically a first separator with an estimated height is inserted by CT or MRI exams. If additional separation is required, the first separator is removed and a second separator is inserted big. However, since the placement of the separators is usually done without the benefit of guide sleeves protectors, changing separators increases the potential for damage to neurovascular structures and may increase the duration of process.

The patent WO-A-9417759 describes a set of Surgical tools for spinal stabilization. Set includes a separator comprising a separator head with a longitudinal axis that defines a single separation height of job.

For bilateral procedures you can insert a double barrel sleeve over a pair of spacers placed previously with a central extension that extends to the inside the disc space to maintain separation. A limitation in the placement of the guide sleeve is the amount of neurovascular retraction that must be achieved to place the Guide sleeves against the disc space. For some patients a double barrel guide sleeve cannot be used because there is insufficient space to accept the set of sleeve. In addition, although the distal end of the sleeve assembly It can be configured to engage with the vertebral surface, if material has been removed from the disc space there is the potential to that adjacent neurovascular structures can invade the work channels found in the disc space, giving as a result damage to these structures caused by contact with the instruments Although some viewing windows in the guide sleeve they can help a better visualization of the steps of the procedure and to verify that the channels of work are not clogged before insertion of tools, the windows themselves can allow the fabric come into contact with the instruments in the working channels. Thus, the need remains to have guide sleeves that require reduced neurovascular retraction for placement appropriate and provide greater tissue protection adjacent.

With guide sleeves in place, the space disc between end plates can be prepared for reception of an implant Typically, cutting instruments are made move forward to extract disc and bone material. Such operations they may require a lot of time since it is often necessary adjust depth limitation equipment and remove instruments to eliminate cutting waste. Since it is desirable to shorten the duration of the operating procedure, follow There is a need to have cutting instruments improved and depth limiting mechanisms.

Although the techniques described above represent advances, it is still necessary to introduce improvements in Instruments and methods The present invention is directed to this need and provides more effective instrumentation to reach it.

The present invention concerns a instrumentation for fusion between vertebral bodies. The present invention provides a separator comprising: a head of separator with a longitudinal axis and a first pair of surfaces opposites that extend substantially along said axis longitudinal and defining a first separation height of work that approximates a normal disc space height; characterized in that said separator head includes a second pair of opposite surfaces that substantially extend to along said longitudinal axis and defining a second height of work separation approaching a second height of normal disc space, said rotating separator head being between said first separation height and said second height of separation by turning said separator head with respect to said longitudinal axis.

The methods for fusion between vertebral bodies in which a separator according to the present can be used invention contemplate getting access to at least a portion of the spine, mark the point or points of entry into space disc, create an initial opening in the disc space through a template, separate the disc space and place a sleeve exterior that defines an internal working channel adjacent to the disc space The template can be inserted in a small size configuration, with a first portion coupling with the fabric. So, the template can be manipulated to a larger configuration for procedures of bilateral insertion by movement of a second portion, without replacing the first portion. Additionally, a template may include guides for trephine that accommodate a variety of cutter heads of different diameter diameters. Specifically, the trephines may include a superior stem with a uniform diameter regardless of head diameter cut of the trephine. Thus, the top guides of the template keep the trephine in axial alignment regardless of whether the lower guide is coupled with the head of the trephine. For keep the alignment of the cutting instruments can be Built-in guide member.

Once one or more openings have been defined initials in the disc space, you can insert a separator from according to the present invention to separate the disc space to the desired height. Multiple separators can be used according to the present invention to separate the disc space. One such separator has a first position that provides a first working separation height in the disc space and a second position that provides a second height of larger work separation. If the first height of work separation is insufficient, you can rotate the quarter-turn separator according to the present invention to create a second height of separation in the disc space. Additionally, in a further preferred aspect of the invention a modular separator mechanism can be configured according to the present invention to accept many separator tips different swivel and can be released releasably to the tips so that a separator tip can be left in the disc space while allowing stem removal of the separating tool. With such a configuration, you can use a single spreader tool stem with several tips, thereby limiting the total number of instruments full separators required. Additionally, they can be done separator tips of a radiolucent material that will not inhibit the optical representation of the disc space by X-rays. Tales separator tips may include radiographic markers for indicate the ends and / or outer edges of the device and markers to indicate the rotary alignment of the separator in the disc space

Once the space separation is achieved desired disc, you can remove the handle of the separator and place a sleeve over the separator. For bilateral access, you can leave one or both spacers in position and place a sleeve double barrel over the spacers, and make them move towards the disc space An additional step that can be done in an example of preferred embodiment is to select a distal tip Removable for the outer sleeve that matches the height of separation of the disc space and with the diameter of the implant. So, to carry out the insertion, an outer sleeve can be used with interchangeable distal tips. Either single or double, the sleeve is advanced until the front portion of the outer sleeve separator is adjacent to the disc space. Yes if necessary, a conductive cap can be placed on the proximal end of the outer sleeve. Then the cuff outside is pushed into position, preferably with a pick or a series of spikes that attach to the vertebrae adjacent to the disc space

Although several sleeves are known in the art, In a preferred embodiment, the outer sleeves have a portion of reduced width next to the distal end to limit the amount of retraction of vascular structures and Surrounding neuronal required for the procedure. In a preferred form, a double barrel sleeve assembly includes a central separation tab with a first height and a pair of opposite lateral extensions that have a second height, less than the first height. Lateral extensions provide protection against tissue invasion inside of the work area in the disc space. An additional aspect of a Preferred embodiment example includes the incorporation of display windows along the outer sleeve for provide visual access to the inside of the working channel while the instruments are in the working channel. For get the desired visualization several window combinations Although visualization is desirable, having openings in the outer sleeve can allow the vessels and surrounding tissue migrate into the canal outer sleeve work. The tissue and vessels present in the working channel may be damaged by insertion and tool removal (often with sharp edges), or while using these tools. So, some covers arranged over the windows can be opened to provide visualization or close to prevent tissue infiltration and glasses, selectively. In addition, the covers or the outer sleeve It can be transparent to allow viewing through the windows without removing the covers or directly through the sleeve. In a similar way, to monitor progress and placement of instruments and implants a system can be used image guidance, such as that which can be purchased under the trade name STEALTH, in conjunction with this system. Even without the use of an optical representation system, it you can use depth limit stops manually adjustable to control the steps of climbing, reaming, scaring  and insert the plug. The term "plug" is used in a broad sense throughout the memory and is intended to cover pins made of bone, metal cage and other implants used to fusion between bodies regardless of the form or material of building.

An outer sleeve can be incorporated with a display window arranged next to a distal end and a cover that covers the window in a removable way. Cover can include a tab next to the distal end to mobilize vessels and other tissues away from the ends of the outer sleeve. In one way, the cover is slidably arranged on the upper surface of the tube or tubes to cover only the windows superior. In another way, the cover is placed so sliding over the tube to cover the upper windows and bottom of the tube.

The outer sleeve may have a double barrel configuration. The bone coupling end of the outer sleeve includes a first tab that has a First height sufficient to maintain separation. Preferably, the bone coupling end also includes a pair of opposite lateral extensions that have a second height less than the first height. Lateral extensions are intended to inhibit lateral invasion of tissue by inside the work area in the disc space, but they are not limited to maintain separation.

An adjustable mounted stop can be incorporated on the tool shank. The cap is likely to be selectively coupled with the tool shank in a plurality of locations along the stem of the tool by axial movement of a collar to check the position of the coupling portions of the stop. With the collar in a first position, the coupling portions they are decoupled from the tool space. With the collar on a second position, the coupling portion is pushed to a coupling with the stem. The tool shank is sized to be received inside an outer sleeve and the stop is sized to prevent the passage inside the sleeve  Exterior. Thus, the stop can be selectively coupled to the stem of the tool to control the extension of the stem of the tool that can be received inside the outer sleeve. Although it is not necessary, in an embodiment example the stop includes a viewing window and the tool shank includes some marks, so that the marks are calibrated to indicate the user spreading tool shank extension beyond a distal end of the outer sleeve.

A reamer can be incorporated with a reamer head that has a plurality of openings of reamed with an internal channel. The internal channel extends inside of the reamer head and in the proximal direction along the minus a portion of the reamer stem. The internal channel includes a proximal segment that extends not parallel to the axis length of the reamer stem, thereby detritus of the reaming can be transferred to the outside of the stem of the reamer.

A method for fusion between bodies is foreseen that comprises placing a template next to a fusion site, forming at least one initial opening in the disc space, separate the disc space using a separator in accordance with the present invention, placing a distal portion of an outer sleeve to the inside the disc space, including the outer sleeve minus a viewing window and a removable cover arranged on the windows, and visualize the surgical site to Through the windows Preferably, the method also includes remove the cover to expose the window before display. In addition, the method may include the enlarge step the opening with sharp tools and can include additionally fix an adjustable depth limit stop when tool shank before extension beyond distal end of the outer sleeve.

Objectives and advantages related to this invention will be apparent from the following brief Description of the drawings.

Fig. 1a is a perspective view of a expandable template.

Fig. 1b is an elevation view of the template of Fig. 1.

Fig. 1c is a front view of the template of Fig. 1a.

Fig. 1d is a top view of the template of Fig. 1a.

Fig. 1e is a bottom view of the template of Fig. 1a.

Fig. 1f is an enlarged perspective view of the coupling end of the template of Fig. 1a.

Fig. 2a is a perspective view of the template of Fig. 1a in an expanded state.

Fig. 2b is a top view of the template of Fig. 2a.

Fig. 3a is a side view of another example. of realization of an expandable template with a prepared trepan inside.

Fig. 3b is a top view of the template expandable of Fig. 3a showing the mechanism of immobilization

Fig. 4a is a perspective view of a guide member and a trepan.

Fig. 4b is an enlarged perspective view. of a portion of Fig. 4a.

Fig. 5a is a perspective view of a separator according to the present invention.

Fig. 5b is an enlarged front view of the tip of the separator of Fig. 5a.

Fig. 5c is an enlarged side view of the tip of the separator of Fig. 5a.

Fig. 6 is a perspective view of a guide sleeve set.

Fig. 7 is a front view of the assembly of guide sleeve of Fig. 6.

Fig. 8 is a side view of the assembly of guide sleeve of Fig. 6.

Fig. 9 is a partial sectional side view cross section of a guide sleeve assembly with a tip removable

Fig. 10 is a joint perspective view of guide sleeve with a cover.

Fig. 11 is an end view of the assembly of guide sleeve of Fig. 10.

Fig. 12 is a front view of an example of realization of a guide sleeve window cover.

Fig. 13 is a front view of an assembly of guide sleeve with the cover of Fig. 12 mounted on the same.

Fig. 14 is a perspective view of a coupling end of a guide sleeve assembly with another example of realization of a window cover.

Fig. 15a is a side view of a cover of window.

Fig. 15b is an end view of the cover of window of Fig. 15a.

Fig. 16a is yet another example of additional embodiment of a window cover.

Fig. 16b is an end view of the cover of window of Fig. 16a.

Fig. 17 is a view front-back of a guide sleeve assembly with a window cover according to Fig. 15 arranged on it, the guide sleeve assembly being arranged in relation to a pair of vertebral bodies and blood vessels adjacent.

Fig. 18 is a partial top view in cross section of a guide sleeve assembly with only one window cover placed on it, extending a portion of the guide sleeve assembly into the space disc

Fig. 19 is a side view of a reamer With a hollow head.

Fig. 20 is the reamer of Fig. 19 rotated 90º with respect to the longitudinal axis of the stem.

Fig. 21 is a partial sectional view cross section of the reamer head of Fig. 19.

Fig. 22 is a side view of a cleaning tool to be used with the hollow head of the reamer of Fig. 19.

Fig. 23 is a top view of the cleaning tool of Fig. 22.

Fig. 24 is a side view of a tap.

Fig. 25 is a side view of a tap It has a removable terrified head.

Fig. 26a is a side view of a reamer It has a removable reaming head.

Fig. 26b is a partial sectional view. cross section of the connection mechanism of Fig. 26a.

Fig. 27 is a perspective view of a stop depth limiter with collar partially retracted to expose immobilization fingers.

Fig. 28 is a partial view of the stop depth limiter of Fig. 27.

Fig. 29 is a cross-sectional view taken along line 29-29 of Fig. 28.

Fig. 30 is a front view of the stop depth limiter of Fig. 27 with the collar completely extended.

Fig. 31 is a side view of an example of alternative embodiment of a depth limiting stop.

Fig. 32 is a partial side view that illustrates the depth limit stop of Fig. 31 in coupling with a tool shank.

For the purpose of promotion and understanding of principles of the invention, reference will now be made to the exemplary embodiments illustrated in the drawings and for describe them a specific language will be used. It will be understood, not However, that no limitation of scope is intended of the invention, contemplating those alterations and additional modifications to the device illustrated, and those additional applications of the principles of the invention according to are illustrated here, as usual for an expert in the technique to which the invention concerns.

The present invention concerns a instrumentation to perform a fusion between vertebral bodies. Specifically, although aspects of the present invention they can have other uses either alone or in combination, the instruments disclosed here are particularly useful for fusion between anterior lumbar bodies.

Referring now to Figs. 1 (a) to 1 (f), they show an intraoperative template 10 to be used in fusion between bodies. Template intraoperative 10 includes a central anchor nail 12 and two supplementary anchoring nails 14 and 16. These nails are adapted to be taken inside the bodies vertebral or other tissue adjacent to the disc space to anchor intraoperative template 10 in an appropriate location. The template 10 includes an outer rod 18 interconnected with a handle 22 and an inner rod 20 disposed within the rod exterior 18. The inner rod 20 extends to encompass the nail 12. The outer rod 18 is rotatable with respect to the rod interior 20. Next to the distal end of the template 10 are arranged guide members 24 and 26 connected to the rod inside 20 and outside stem 18, respectively. Preferably, the guide members 24 and 26 are plates substantially circular that have an opening in them. Guide members 24 and 26 define openings 28 and 30, respectively, adapted to receive a tool through it of trepanation. Along the outer rod 18 are arranged tread guides 34 and 36 having openings 40 and 42, respectively, aligned along an axis 31, and sized to receive a shank of the climbing tool. In a alternative embodiment example it is contemplated that the rod interior 20 may be connected with guide member 26 and the outer rod 18 may be connected to the guide member 24.

In a first small size configuration for unilateral squeezing and guidance, shown in Fig. 1a, guide members 24 and 26 are axially aligned along of axis 31 with openings 28 and 30, respectively, in a similar alignment. In this small size configuration, the expandable template can be inserted inside the body to through a relatively small opening and the template can be used for a clamping and unilateral guidance of a trephine. In this position, a trephine can be guided through the guides 34 and 36 and guide members 24 and 26 until coupled with the fabric existing below. In addition, referring to Fig. 3a, a trepan can have a uniform diameter along the largest part of its stem, so that there is a tight fit inside of guides 34 and 36. The fitting fitted in guides 34 and 36 maintains axial alignment while allowing rotation of the stem of the trephine. Thus, a single template 10 can be used with a variety of diameter sizes of the trepan head, to condition that the stem has a diameter substantially uniform.

Referring now to Fig. 1a, a handle 22 is connected to the outer tube 18 and can be rotated in the direction of arrow 32 for a clamping position and bilateral guidance This action rotates the outer rod 18 with respect to the inner rod 20. The guide member 26, the guide 34 and  the guide 36 are connected to the outer rod 18 and, by consequently, they rotate when handle 22 is moved. On the contrary, the first guide member 24 is interconnected with the rod inside 20 and remains stationary while turning of the handle 22. As shown in Fig. 2a, the handle 22 is rotated approximately 180º to align the second template 26 approximately 180º from the first template 24, and with this expand the template to its trepanation position bilateral. Thus, a procedure of trepanation along an axis 33 through guides 34 and 36 to cut an opening in the disc space. Axis 33 is separated from axis 31 by a distance "D" representing the separation distance between the midpoints of the implants a insert. Figs. 2a and 2b show the first and second templates rotated 180º with respect to each other. Fig. 2b shows a top view of a clamp configuration and bilateral guidance In this expanded configuration, the edges exterior of guide members 24 and 26 define the total area necessary for placement of implants and instruments with a specific configuration and size. Although in an example of preferred embodiment cylindrical implants with diameters of 16 mm 18 mm, or 20 mm, it is contemplated that they can be used other diameters and other shapes such as, but not limited to, squares and rectangles.

Shown by dashed lines in Fig. 2b there is a regatta 39 formed in the guide member 24 and a projection 37 defined in guide member 26 and extending to the inside the race 39. It will be understood that the coupling between race 39 and projection 37 maintains alignment and limits the 180º turn. Thus, the template 10 can be moved between the Small size configuration and expanded configuration, but the coupling between the regatta and the projection limits a movement additional and will provide a positive indication of the 180º turn, thereby eliminating the need for visual alignment With the first position.

Referring on time to Fig. 3a, in the an example of a further embodiment of a expandable template in accordance with the present invention. A template 600 is substantially identical to template 10 previously stated above, with the exception that the template 600 includes an immobilization mechanism 613. The expandable template 600 includes a 626 handle connected to a outer rod 622. As in the first embodiment, the template 600 includes a first guide member connected to a inner rod 624 and a second guide member 606 connected to the outer rod 622. The first guide member 608 includes a barb 612 and an inner rod 624 extends to form a barb central 610. The outer rod includes guides 602 and 604. Such As shown in Fig. 3a, a tread 601 can be placed at through guides 602 and 604, and through guide member 606. The cutting head 605 includes cutting teeth 611, a series  of index marks 607 and a window 609 to visualize the hollow interior content. Preferably, step 601 includes a central cannula 603 that extends from the handle to The cutting head.

Between the inner and outer stems is arranged an immobilization mechanism 613 to prevent the rotation. Referring to Fig. 3b, an arm of immobilization 614 is pivotally attached to the rod inside 624 by a pivot pin 620. The arm of immobilization can be pivoted on the inner rod until extending through a groove 616 in the stem exterior 618. It will be understood that with the immobilization arm arranged in the grooves, the inner and outer stems will look prevented from turning. In a first immobilization position, the stems are aligned as shown in Fig. 3a in the expanded bilateral clamping configuration. It will be understood that the swivel, expandable template of the present invention allows the insertion of the device through a smaller opening than what would have been allowed with a template with double fixed ratio trepanation opening. In addition, the template expandable can be immobilized in either a unilateral position or bilateral The immobilization coupling in position bilateral ensures precise bilateral placement with a consistency that could not be easily achieved with a template unilateral, particularly when the surgeon must replace the device by visual alignment. Subsequently, he can make device up to a suitable expanded configuration to guide the trephine to form bilateral openings without removing the instrument.

During use, access to a anterior portion of the spinal column by a known method. Blood vessels, particularly the aorta, vena cava and some branches of them are mobilized to provide a space for the placement of a bilateral implant. With the template in the reduced size configuration of Fig. 1a, the template inside the body and advanced until the nails are arranged next to the disc space. Girth of the template guide member is selected with respect to the circumference necessary for the bilateral placement of a pair of implants More specifically, the area of guide members of Fig. 2b approaches very close to the area necessary for the placement of a double barrel guide sleeve shown here, see, for example, Fig. 11. The central nail 12 is arranged centrally between the location provided for the implants. Already either in the unilateral or expanded bilateral state, the template can be arranged next to the disc space to measure the available space for implant placement and instrument. If the space seems to be too small, it can Insert a smaller template to evaluate the space. In the bilateral state, the workforce approaches the necessary area for placement of the implant and the instrument. Can be it is necessary to mobilize the vessels arranged within the area of presentation of the template outside the area, or a Implant size or alternative access. In addition, osteophytes that appear within the template area can be removed to prepare a coupling with a guide sleeve. Once has cleared the area, the nails are inserted into the fabric of the disc space and / or adjacent vertebrae to anchor the template, thereby maintaining its position during the steps subsequent. As shown in Fig. 3a, a trephine is inserted into the guides and through the members of guide. The trephine is advanced sharply into the interior of the tissue of the disc space to form an opening in it. He trepan can then be removed at least partially from the template to allow movement between guide members first and second. If an immobilization mechanism is used, it you must move the immobilization arm to a position unlocked and turn the handle to rotate the guide member upper to expanded bilateral clamping position. Be reinsert the trephine and advance through the guide member upper to form a second opening aligned with the first opening and displaced a distance D from it. So, the template allows the controlled formation of bilateral openings through an expandable and foldable template. The template can be folded to its reduced size form and removed once the trepanation operation completed.

Referring now to Figs. 4a and 4b, in they show an additional guiding device according to the present invention A guide member 450 includes a stem elongate 430 having a substantially uniform diameter over most of its length. Stem 430 includes a portion distal adapted to guide a cutting instrument that has a hollow cutting head The distal portion of the stem 430 includes a distal end 432 having a sharp point 434 adapted to penetrate tissue, specifically tissue arranged in space disc The distal end 432 includes marks 444 indicating the extension of the stem 430 arranged in the disc space. Though the guide member is preferably formed of steel stainless, other biocompatible materials are contemplated. Specifically, the stem 430 may be formed of a material radiolucent and the 444 marks can be radiopaque. Next to distal end 432 there is an enlarged portion 436 that has a diameter substantially larger than the diameter of the stem. The enlarged portion 436 is adapted to prevent further advance of guide member 450 into the fabric and to guide the cut of the cutting tool. The enlarged portion 436 includes preferably a substantially flat surface 442 perpendicular to the longitudinal axis of the stem 430. Next to the flat surface 442 a surface substantially disposed spherical This is followed by a conical surface 438 decreasing that is adapted to align the cutting head over the enlarged head 436. It will be understood that the inner surface of the cutting head 426 defining the opening 428 is coupled to the transition line 448 between spherical surface 440 and the decreasing surface 438. The diameter of the transition line 448 substantially coincides with the internal diameter of the head 426 cut to provide a tight fit in order to Keep the alignment.

During use, guide member 450 is inserted into the body with the distal end 432 completely inserted into the tissue of interest, preferably tissue from the disc space, although contemplated other uses. The cutting tool 420 is advanced on the guide member 450 with rod 422 in substantial alignment with the stem 430 extending through channel 427. Although a trephine has been illustrated, with guide members according to the present invention other cutting tools can be used, such as, but not limited to, reamers and tools non-rotating cut. Next to the enlarged portion 436 are located cutting teeth 425 that are advanced until sharp teeth surround the enlarged portion. It will be understood that if the cutting teeth are displaced with respect to the enlarged portion 436, the teeth will be coupled with a portion of conical surface 438 and with it will be pushed to the alignment. The enlarged portion 436 is received within the chamber 428 and cutting teeth 425 are advanced along of a distal portion 432 until the conical surface 428 is rests on the inner conical surface 429 to prevent an advance subsequent. The set can be removed with the cut tissue impaled by distal portion 432. The tissue can be removed from chamber 428 by advancing the guide member with respect to the cutting head so that the enlarged portion pushes the tissue Outside hollow interior. This can be particularly practical. when the cutting tool is used to remove bone graft. The penetration depth of cutting teeth can be adjust by placing the enlarged portion. Additionally, although only a single enlarged portion is shown, more than one can be placed on the stem to adjust additionally the depth of the guide member and the depth of cutting the tool.

Referring now to Figs. 5a-5c, they show a space separator disc 50 according to an aspect of the present invention. He spacer 50 includes a proximal end 53 configured as a elongated end to mate with a Hudson connection conventional on a T-handle (not shown). A stem 54 is attached to a spacer tip 56. Although a stem is shown and an integral head, the head 56 may be fixed so removable to the stem 54. One such removable fastener is exposed more fully in the patent US-A-6428541. Separator tip 56 is designed in such a way that it can be inserted into a disc space to establish a first separation height of work 72 (see Fig. 5b), which is smaller than a second working separation height 70 (see Fig. 5c). Plus specifically, separator tip 56 has a leading edge rounded 62 extending to inclined surfaces opposite 58 and 59 that extend in the most proximal direction merging respectively with opposite surfaces 60 and 61 substantially flat. Flat surfaces 60 and 61 are extend in parallel alignment along the longitudinal axis of the  separator to set the height 72. It will be understood that the inclined surfaces 58 and 59 cooperate to facilitate insertion inside the disc space and to initially separate the disc space at least up to a height 72. If the first height 72 is sufficient, further processes can be carried out according to are known in the art to effect the insertion of a implant. Alternatively, the rounded leading edge 62 allows that the separator is inserted until directly achieving the second separation height 70.

In an alternative aspect, in the case that the height 72 was insufficient, head 56 can be rotated quarter turn, or 90º, to the position shown in Fig. 5C. Rounded surfaces 64 and 66 are attached to the bone to push it apart to a second separation height 70, higher. It will be understood that the use of a separator tip such as that disclosed in the present invention allows a separation of two heights of the disc space that can be carried out with a single instrument and without removing the disc space instrument. This offers the surgeon an advantage. consisting of a single instrument that offers multiple heights of Useful separation Thus, the surgeon may initially believe that a disc space will need a first amount of separation, After insertion of the separator, the surgeon can discover that an additional separation is required. In this situation, a separator according to the present invention allows a further separation without removing the instrument. In addition, the head of separator 56 limits the number of instruments that should be put to the surgeon's willingness to perform a procedure surgical providing two heights of work separation in a only useful. Specifically, but without being a limitation, the separator heads can be formed with first heights 72 in a range of 6 mm to 12 mm and second heights in a range of 7 mm to 13 mm. Preferably, heights 70 and 72 vary by increments of 2 mm. More preferably, the height 72 is 8 mm and the height 70 is 10 mm. In another way, the height 72 is 10 mm and the height 70 is 12 mm. Other may be used. variations that provide work separation heights that they approach the disc height in a normal spine.

Referring now to Fig. 6, is she shows a double barrel guide sleeve assembly that has a first sleeve 140 connected to a second sleeve 142. The sleeves 140 and 142 each define working channels 130 and 132 that extend in a substantially unobstructed manner from the proximal end 102 to the distal end 104. The set 100 includes upper windows 106 and 108 formed in sleeves 142 and 140 respectively, which are adapted for the coupling by means of an extraction tool. Sleeves they also include lower display windows 110 and 112 elongated

Next to the distal end 104, the thickness of the material is reduced along the outer edge of each tube 140 and 142 in order to provide a cross-sectional area smaller for the sleeve assembly as well as a reduced width in the transverse extension to the longitudinal axis of the assembly. The area of reduced cross-section and the smaller width reduce the amount of retraction of vessels adjacent to the disc space that It would be necessary without reduction. A side wall 114 is shown as an indication of the reduced thickness of the device in the area distal 104.

The distal end 104 includes a flange of central separation 116 that can be inserted inside the disc space to achieve or maintain a height H1 of separation between two vertebral bodies. Side tabs 118 and 120 also extend partially inside or next to the disc space However, in an embodiment example preferred, side tabs 118 and 120 have a height H2 which is less than the height H1. Thus, they do not produce a separation of the disc space but they are planned mainly to protect the vessels and neurological structures surrounding being damaged during procedures. Although this it is the function of the side tabs in the embodiment example preferred, it is contemplated that they may be sized to provide separation within the disc space along with the central tab 116. Additionally, distal end 104 includes a few spikes 122, 124, 126 and a fourth spike that is not visible of Fig. 6. These spikes can be pushed into the bone of the adjacent vertebral bodies to withstand the cuff of 100 double barrel guide in a fixed position in relation to the vertebral bodies It will be understood that windows 110 and 112 provide medical staff the opportunity to visualize the instruments as well as openings in the disc space and bodies vertebral, without completely removing instrumentation from guide sleeve 100.

Referring more specifically to Fig. 7, the double barrel guide sleeve 100 is shown in a view front to further illustrate an additional aspect of the invention. At one end opposite the coupling end to the vertebrae 104, the guide sleeve has a width W1 which is approximately twice the diameter of one of the sleeves. Together to the end to the coupling end to the vertebrae 104 of the sleeve, each of the outer portions of the sleeves it has a reduced wall thickness in the side walls 113 and 114. The walls are not completely flat, but have a substantially greater radius of curvature (see Fig. 11) that gives the appearance of substantially flat walls but that provide a reduction in wall thickness over an area greater and that converge towards the full wall thickness in the terminations of the side walls 113 and 114. The thickness of reduced wall on the side portion of each tube reduces the width general of the device up to a width W2. The reduction in width decreases the amount of retraction to which they should be displaced vessels that are in the area. The reduction of desired width is effected with a small reduction in the device resistance since a large part of the structural integrity, particularly resistance to axial compression during insertion of the sleeves, is carried to out through the much thicker central portion where the two sleeves join together. Preferably, the central portion It can have a thickness equal to two wall thicknesses of the tube.

As an additional alternative, Fig. 9 shows that the guide sleeve assembly 190 may be provided with 191 removable barrel tips that have separation heights, lateral extensions or distribution of different spikes. The barrel tips can also have different diameters corresponding to the placement of implants with diameters different. The removable tips 191 can be held in place by any of a variety of known connection mechanisms. However, in a preferred embodiment, the set of guide sleeve 190 includes a pair of flexible fingers 192 and 193 opposites, which have protrusions 194 and 195, respectively. The protrusions 194 and 195 of flexible fingers 192 and 193 extend inside slots 196 and 197, respectively, defined in  The removable tip. To limit the proximal movement of the tip 191 during insertion, a wedge surface 198 is coupled by support with a shoulder 199 and the central portion between the tubes of superior guide. The use of a removable tip not only allows the use of interchangeable tips to suit an application specific, but also allows the extraction of the cuff exterior after placement in the body. With just one tip 191 instead, you can more easily view and access the posterior aspect of the disc space or spinal canal.

Referring now to Figs. 10 and 11, in they show an additional embodiment of a sleeve of double-barrel guide similar in most aspects to outer sleeve 100 of Fig. 6. The exemplary embodiment additional of Fig. 12 differs from that of Fig. 6 in that the sleeve Guide 100 included only a single elongated viewing window For each sleeve. In the double 150 barrel guide sleeve, each sleeve has a total of four windows, two on one surface upper and two on a lower surface. So, as shown in Fig. 10, windows 152, 154, 156, 158 provide the surgeon the opportunity to visualize throughout most of each work channel. The back of the guide sleeve 150 has a similar configuration. Guide sleeve 150 is used in a manner similar to that of outer sleeve 100. In one example of preferred embodiment, the outer sleeve 100 is provided with a cover 160 having a length 162 sufficient to cover the four windows arranged on at least one side of the device. The cover 160 is incorporated to prevent possible tissue damage that could invade the working channel to through the windows and that could be damaged by the operation, insertion or removal of tools in the working channels It is contemplated that cover 160 may be transparent to allow viewing directly through of the cover or that it may be opaque, requiring that the Cover be repositioned before viewing. Additionally it contemplates that the cover may be of sufficient length 162 so that it extends over all existing windows on one side and may be suitable to selectively cover either the windows proximal 156 and 158 or all windows. A leading edge 163 It is wedge-shaped to prevent tissue damage, particularly when moving forward to cover the windows The wedge could push the tissues out pulling them away from the cuff. In addition, cover 160 includes a depression 171 substantially following the contour between the pair of guide sleeves.

Although other binding mechanisms are contemplated, the cover 160 is held in place, as shown in the Fig. 11, by means of a retaining pin 170 connected through cover 160 to a lower portion in dovetail 172. The dovetail portion 172 is likely to slide along of a dovetail groove defined by slots 168 and 169 defined inside the outer body of the guide sleeve 150.

Figs. 10 and 11 show an example of realization of a sliding cover and selectively covering a plurality of windows in the outer sleeve 150. Figs. 12 to 16b illustrate even more examples of embodiment of a cover that can be moved to expose some windows underlying in one of the double barrel tubes. In addition, although the decks are disclosed for use with barrel assemblies double, it is contemplated that they can be used with sleeves of guide of a single tube without excessive modifications. In the Additional embodiments, the channel of work and viewing windows of one of the canyons while a deck remains in place over the canyon alternate.

Referring to Fig. 12, a cover partially cylindrical 182 consists of elongated portions 183 and 185 that are sized to cover windows of underlying visualization. Elongated portions are retained on the guide sleeve by means of connectors 184 and 186 that are sized to extend around the outside of the tube exterior and of a guide portion 188. It is contemplated that connectors 184 and 186 can be coupled with a cover portion on the opposite side of the guide sleeve identically to the shown in Fig. 12. While cover 182 is disclosed having elongated members 183 and 185 interconnected, it contemplates that each of the covers 183 and 185 can be separate to allow viewing of windows only in one upper or lower surface of the work tube without opening the opposite window.

Referring to Figs. 14 to 16b, in they show even more examples of cover realization of window. Fig. 14 shows a cover 510 that covers approximately 200º of a single sleeve 502 of the set of guide sleeve 501, similar to that of Fig. 6. The cover includes an internal passage 515 and is likely to slide along the sleeve 502. In an additional aspect, the cover 510 includes a elongated tab 512 adjacent to a coupling end to the bone 504. Between flange 512 and the outer diameter of the deck 510 extends a wedge surface 513. Doing now reference to Figs. 15a and 15b, a cover 514 includes a tab 516 that extends along the entire leading edge of the cover. The cover extends in the form of a cylinder Partial missing material over an angle 517.

The angle 517 is approximately 160º, so that the material extends around approximately 200º of the cylindrical. It will be understood that covers 510, 514 and 520 they can be configured so that they have material extending more than 200º around the cylinder to allow cover rotation in relation to a guide sleeve, of so that the cover can rotate to discover a window. Thus, for covers 510 and 514, the tabs can continue to aim the vessels away from the guide sleeve even when are displaced to allow access through windows

An alternative embodiment shown in Figs. 16a and 16b does not include the enlarged tab 512. A cover 520 has a uniform end 524 and defines a channel internal 522 adapted to receive a guide sleeve. But nevertheless, In certain surgical procedures, it is desirable to use the example of realization that has the tab to protect the vessels that are in close proximity and to push them away from the distal end of the guide sleeve where it might be possible for They will come into contact with instruments arranged inside. Without the use of a cover, the outer sleeves cannot fit with the shape of the vertebral body surface thereby allowing the potential for contact between some instruments inside the outer sleeves and the vessels in close proximity. It is particularly dangerous when It operates near the vena cava and the aorta. However, as is shown in Figs. 17 and 18, the tabs on the covers they act as a retractor to push the vessels away from the outer sleeves

Referring more specifically to Fig. 17, a guide assembly 550 has been inserted into a disc space D between two adjacent vertebrae V1 and V2. Adjacent to the guide assembly 550 are arranged glasses 562 and 560 graphically depicting portions of the aorta or vein digging. On guide tubes 552 and 554 are mounted respectively, covers 556 and 558. Tabs located in the covers, shown more clearly in Fig. 15a, push the vessels away from the guide tube and, more importantly, moving them away from working channels 553 and 555 where they would be tools inserted Vessels 560 and 562 are in a closer proximity with tubes 552 and 554 near V1. So, side extensions that are in the guide assembly can be insufficient to prevent contact between the vessels and the tools in all applications.

Referring now to Fig. 18, in it a top view of a 580 guide assembly placed is shown in the disc space next to a vertebral body 591. The set of guide 580 includes a central separator 582 and extensions laterals 584 and 586. Barbed 590 and 592 may be inserted in the bone of the vertebral body. With an illustrative purpose, a cover 596 has been placed on a first guide tube while that a guide tube 595 with windows 593 remains uncovered. The bone coupling end 594 does not fully adapt to the vertebral surface 589, thus allowing the possibility of a migration of the vessels into the working channels. The cover 596 with the tab 598 pushes a glass 599 away from a coupling between the coupling end to the bone 594 and the bone surface 589. On the contrary, a glass 597 is placed next to the interface between the guide tube and the bone, resulting in a potential for vessel migration to inside the working channel through the space between the end of coupling to bone 594 and bone surface 589. Thus, the  covers can also be useful to further retract the vessels away from the interface between the coupling end to the bone of the guide assembly and the bone surface.

Referring now to Figs. 19 to 21, in they show a reamer 200. Fig. 20 shows the reamer 200 of Fig. 19 rotated 90 °. Reamer 200 includes a cutting head 202 which has a cutting groove 203 with 205 gutters arranged between them. In a gutter 205 an opening that extends to a channel is arranged interior 209. A series is defined in the cutting gutters of openings 204 that communicate with the inner channel 209. The inside of the cutting head 202 is hollow and forms a channel inner 209. The inner channel 209 has a first portion with side walls substantially parallel to the axis longitudinal and a second portion defined by walls exteriors that extend at an angle to the axis longitudinal. Preferably, the second portion extends forming a non-orthogonal angle to allow easy cleaning. The  second portion is connected to an opening 208 formed in the outer surface of the stem and away from the cutting head. Be understand that opening 208 allows the material cut by reamer head 202 travels through the channel interior 209 until exiting the opening 208. In addition, a segment of reduced diameter 211 defines an area between the stem the sleeve outside where the detritus from the cutting operation can  be collected before device removal. This area of collection has, in a preferred embodiment, a length 214, although it is understood that it can be extended to Increase the volume of material that can be collected. This configuration allows to complete the cutting operation without the need to remove the reamer to clean the detritus picked up Additionally, the detritus can be visualized at through the windows of the outer sleeve to make a evaluation.

A rod 211 of reduced diameter extends in the proximal direction to a conical region 210, which expands to a guide portion 212 of larger diameter. The region Conical 210 helps with easy insertion and guidance of the stem of the reamer inside an outer work sleeve, as it has been  exposed above. The guide portion 212 of larger diameter It is sized to have a reasonably tight fit inside an outer work sleeve to allow rotation of the device, however limiting the amount of movement transverse inside the tube to ensure precise reaming inside the bone The reamer 200 can therefore be guided through a guide sleeve. Stem 216 interconnects the end  proximal to enlarged area 212.

On the stem 216 are arranged a series of numbers 218, which indicate the depth at which extends the reamer inside the bone, beyond the edge of a cooperating guide sleeve. As can be seen from of the examination of Figs. 19 and 20, the numbers are shown in a staggered arrangement around the circumference of the stem 216. This staggered arrangement allows each number to be more large, in the preferred embodiment, three times more large, than it could be if all the numbers were listed in a single column throughout the device. Like this arrangement allows easy viewing of numbers by the surgeon despite a small incremental adjustment of the device, preferably increments of 1 mm. Extending in one direction more proximal along the stem 216 are a series of slots 221, which are adapted to couple with a depth limit stop mechanism (further described below) to adjust the reaming depth of the device. On the proximal end 220 is a connection Hudson type for coupling with a T-handle or other type of mango.

Referring now to Figs. 22 and 23, in they show a cleaning tool 700 adapted to be used with the hollow reamer head described above. The useful of cleaning 700 includes a head 702 that has a diameter that substantially coincides with the diameter of an internal chamber 209. Cleaning tool 700 includes a flexible portion 704. The flexible portion 704 is connected to a rod 708 which is connected to a handle 706. Flexible portion 704 allows the device enters through an opening 208 existing in the reamer and force the material out through the open end 201 of the reamer head as a end 710. This is an improvement over those reamers of Hollow head that do not provide a cleaning outlet channel.

Referring now to Fig. 24, in it a thread thread tap 230 is shown to ground a Reaming bone space. The die 230 includes a cutting head 232, and a rod 233 of reduced diameter adjacent to the head 232 to provide a space around the rod between the tube  exterior for the collection of detritus from the operation terrified. A conical surface 234 extends to an area 236 of greater outer diameter. As explained previously with respect to reamer 200, conical surface 232 allows guiding the tap inside a guide sleeve and a Enlarged area 236 providing a reasonably tight fit with the guide sleeve to maintain the axial alignment of the tap 230. Tap 230 includes staggered 240 marks incrementally and a Hudson 242 connection as described previously with respect to reamer 200.

Referring now to Figs. 25 to 26b, they show some modular cutting tools attached to a stem Fig. 25 shows a rod 250 coupled in a manner releasable to a threading head 252 by a coupler 254. In a similar manner, the rod 250 is coupled to a head of reaming 256 via a coupler 254. In Fig. 26a, the head reaming 256 can be removed from rod 250 at the connection 254. The reamer includes a 256 reaming head that has only six cutting openings arranged around the head and a hollow inner chamber connected to openings 258. Although you can use any one of a number of connection mechanisms known, Fig. 26b shows the use of a susceptible collar 260 if axially displaced to release balls 262 and 263 of slots 264 and 265 of the reamer head. 250 stem includes a hollow extension 268 that has openings 270 and 271 to withstand balls 263 and 262, respectively. Collar 260 includes a portion of reduced diameter 276 adapted to push the balls 262 and 263 inside the slots 264 and 265, with the In order to immobilize the cutting head and the rod together. He collar 260 can be displaced axially away from the head cutting to arrange an enlarged inner diameter portion 278 next to the balls to allow them to disengage from the slots 264 and 265, thereby allowing the cutting head to decoupling the rod. The same mechanism can be used with a variety of cutting heads.

Referring now to Figs. 27 to 31, in they expose a depth limit stop mechanism liable to cooperate with the stem of a tool and a guide sleeve as previously described. Such tools can include, without being a limitation, a reamer, a tap, and an implant inserter. A cap of depth limit 326 includes a support shoulder 330, circumferential, enlarged, adapted to engage with one end proximal of an outer working sleeve to prevent a further advance of the stop and any interconnected rod. He top 326 also includes 328 viewing windows for allow viewing of existing depth marks on a rod that extends inside the stop. The top 326 includes a manually operated collar 332, which can be axially displaced to allow the fixation of fingers 334. Collar 332 is normally pushed to a position extended by a pier 342.

Referring specifically to Fig. 29, fingers 334 include protrusions 336 that extend internally and a support surface 337 that extends externally. Internal projections 336 are configured for a coupling within slots 221 (Fig. 20) defined as length of the stem of a work tool, and the surface of bearing is configured to engage collar 332. Additionally, each finger includes an outer wedge portion 339 adapted for coupling with support surfaces 340 of the collar 332 to push the fingers in as it is done advance the collar. It will be understood that in a retracted position, the bearing surface 340 of collar 332 will be substantially decoupled from wedge 339 and allow fingers 334 to decoupling the slots 221 of a work rod (Fig. 20). With collar 332 in the extended position shown in Fig. 29, the support surfaces 340 will charge against the surfaces of support 337 of each of the fingers to push the projections 336 inside the slots 221 of the tool shank. For release the fingers, collar 332 can be displaced in the direction of the arrow R until the support surface 340 is move past the wedge surface 339. Then the fingers Flexible can move elastically out. In this way, a user can quickly and easily decouple the mechanism from stop immobilization to move forward or backward one work tool and then reattach the stop on the desired position. Preferably, a distal collar end 333 332 will extend beyond fingers 334 to limit the possibility that surgical staff can hook rigging protector on exposed fingers.

In a first embodiment shown in Fig. 30, collar 332 is retained in a housing 334 by a retaining pin 342 extending into the interior of the housing and through a slot 344. The retaining pin 342 allows axial displacement of collar 332 relative to the body 334, as well as a slight amount of rotation within the groove. L-shaped slot 346 will be understood to allow the mechanism depth limit stop be immobilized in one position decoupled that allows a free movement of the stem of the tool through the depth limit stop. This is one desirable construction in some cases for easy removal of the tool shank, as well as for a display of the tool without the limitations of the limit stop mechanism deep

Fig. 32 shows a limit stop of depth 326 coupled with a tool shank that has 360 slots and 362 marks to show the depth of the distal end of the tool outside the guide sleeve 370. A support shoulder 330 is sized to engage with the guide sleeve to prevent further movement. Be understand that penetration depth can be adjusted between a number of positions defined by the coupling of the 336 fingers in the grooves 360 of the tool shank. He adjustment is easily made by axial movement of the collar 332. The coupling with the tool shank is indexed by the separation of the grooves 360 existing in the stem of the tool, so that you can easily know the position exact top. The tool shank can be rotated with respect to the stop mechanism to show the depth number 362 appropriate in window 328.

Claims (14)

1. A separator (50) comprising: a separator head (56) having an axis longitudinal and a first pair of opposite surfaces (60, 61) that extend substantially along said longitudinal axis and that define a first working separation height (72) that approaches a normal height of a disc space; characterized in that said separator head (56) includes a second pair of opposite surfaces (64, 66) that extend substantially along said longitudinal axis and define a second working separation height (70) that approximates a second normal height of a disc space, said separator head (56) being rotatable between said first separation height (72) and said second separation height (70) by rotating said separator head (56) around said axis longitudinal. 2. A separator according to claim 1, wherein said first working separation height (72) is 10 mm and said second working separation height (70) is 12 mm 3. A separator according to claim 1, wherein said first working separation height (72) is 8 mm and said second working separation height (70) is 10 mm 4. A separator according to claim 1, wherein said first working separation height (72) is less than said second work separation height (70). 5. A separator according to claim 1, wherein said first pair of opposite surfaces (60, 61) It comprises substantially flat surfaces. 6. A separator according to claim 1, wherein said second pair of opposite surfaces (64, 66) It includes rounded surfaces. 7. A separator according to claim 1, wherein said separator head (56) includes an edge rounded front (62). 8. A separator according to claim 1, wherein said separator head (56) includes an edge rounded front (62) extending to a couple of inclined surfaces that extend in one more direction proximal to said first pair of opposite surfaces (60, 61). 9. A separator according to claim 8, wherein said first pair of opposite surfaces (60, 61) is extends substantially parallel to said longitudinal axis. 10. The separator of claim 1, in the that said separator head (56) is rotatable between said first separation height (72) and said second separation height (70) by turning said separator head (56) of ninety degrees around said longitudinal axis. 11. A separator, according to the claim 1, wherein said second pair of surfaces opposite are rounded surfaces (64, 66) adapted to engage with the bone and push it to separate it until said second separation height (70) as a result of said rotation. 12. A separator, according to the claim 1, further comprising a rod (54) attached to said separator head (56). 13. A separator, according to the claim 12, wherein said rod (54) is attached from removable manner to said separator head (56). 14. A separator, according to the claim 12, wherein said rod (54) is attached from integral manner with said separator head (56).